Removing myself from OWNERS.

Adding mohsen@ as the owner for gesture navigation.

Bug: NONE
Change-Id: Ia87c5bdfedbc899f828306b3fa7c33cb8685fd1c
Reviewed-on: https://chromium-review.googlesource.com/774995Reviewed-by: Mohsen Izadi <mohsen@chromium.org>
Commit-Queue: Mikhail Fomitchev <mfomitchev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517597}

ash/drag_drop/OWNERS

-mfomitchev@chromium.org

content/browser/web_contents/aura/OWNERS

-mfomitchev@chromium.org
+mohsen@chromium.org
 sadrul@chromium.org

ui/touch_selection/OWNERS

-mfomitchev@chromium.org
 mohsen@chromium.org